1. Field of the Invention
The present application relates to the use of a triethanolamine product mixture having a low content of diethanolamine and monoethanolamine in functional fluids, such as lubricants, metal working fluids and hydraulic fluids.
2. Description of the Related Art
The use of triethanolamine in a variety of industrial fluids is well known. Triethanolamines are normally produced in one or more steps by ethoxylating ammonia with ethylene oxide. In order to avoid the formation of polyalkyleneglycol chains, HOC.sub.2 H.sub.4 (OC.sub.2 H.sub.4).sub.n, where n&gt;0, and quaternization the nitrogen, atom the ethoxylation is normally stopped, when the reaction mixture contains 60-90% by weight of triethanolamine and 10-40% by weight of diethanolamine and monethanolamine. Such a reaction mixture may be subjected to distillation to obtain purer triethanolamine. The fact that the triethanolamine reaction product contains a large amount of diethanolamine has not previously been considered a real drawback, as diethanolamine contributes to anticorrosion properties, low foaming and desired alkalinity when used in functional fluids.
Recently, more attention has been paid to the fact the diethanolamine is toxic and forms nitrosamines, which are carcinogenic in animal tests. Therefore, a reduction of the content of diethanolamine is desirable. The content should, according to recommentations, be less than 1% by weight.
Thus, one object of the invention is to produce a triethanolamine product mixture which contains diethanolamine in an amount less than 1% by weight. This triethanolamine product mixture shall at least have about the same corrosion inhibiting ability and/or defoaming properties in functional fluids.
Another object of the invention is that the method of producing a triethanolamine product mixture shall be simple to perform and that the mixture shall be usable without any additional cleaning and/or working-up processes, such as distillation.
Still another object of the invention is to keep the formation of quarternized triethanolamine and polyalkylene glycol chain containing ethanolamine products to a low level.